New digital recordings of events in U.S. history and early radio shows are at risk of being lost much faster than older ones on tape and many are already gone, according to a study on sound released Wednesday.

Even recent history - such as recordings from 9/11 or the 2008 election - is at risk because digital sound files can be corrupted, and widely used CD-R discs only last three to five years before files start to fade, said study co-author Sam Brylawski.

"I think we're assuming that if it's on the Web it's going to be there forever," he said. "That's one of the biggest challenges."

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The study also calls for legal reforms to enable more preservation. A hodgepodge of 20th century state anti-piracy laws has kept most sound files out of the public domain before U.S. copyright law was extended to sound recordings in 1972. The study found only 14 percent of commercially released recordings are available from rights holders.

Later this year, the library will debut a National Jukebox online after securing a license to stream sound recordings controlled by Sony Music Entertainment.

This is the first comprehensive, national-level study of the state of sound recording preservation ever conducted in the U.S. The authors, Rob Bamberger and Sam Brylawski, have produced a study outlining the web of interlocking issues that now threaten the long-term survival of our sound recording history. This study tells us that major areas of America's recorded sound heritage have already been destroyed or remain inaccessible to the public.